Gear & Gadgets —

A look at Android 5.1: speed, security, tweaks

Though not a huge update, 5.1 brings a few worthwhile changes.

Four months after the first release of Android 5.0 Lollipop, Google has followed up with a second version: Android 5.1. The speedy turnaround time compared to Android 5.0 (which appeared a year after 4.4) means that there aren't many large-scale changes to look at—but the release does feature numerous little improvements and tweaks.

It’s faster! (on the Nexus 6, at least)

5.1 brings much faster random read and write speeds to the Nexus 6, and the Nexus 5 improves a little, too.

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Sequential speeds are about the same, meaning large games take just as long to load as 5.0.

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In the CPU chart at the bottom of these two screens, you can see that 5.0 will shut off CPU 3 and 4 when nothing is happening, but 5.1 keeps everything running and ready.

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5.1 seems to have eliminated many of the performance issues with the Nexus 6. When we initially reviewed the device, the Nexus 6 was slower at loading apps and switching tasks than the older Nexus 5 had been. With 5.1, the newer phone feels much snappier; with non-game apps, it can now keep pace with the Nexus 5.

On benchmarks, we're seeing much higher random read and write scores on the Nexus 6 with 5.1; random read gets a 2x speed boost, while random write is a whopping 9x faster. The same dramatic speed boosts aren't present on the Nexus 5, and we suspect the difference is that the Nexus 6 is encrypted while the Nexus 5 is not. According to Francisco Franco, a longtime third-party Android kernel developer, Google is now using NEON instructions on the Nexus 6 to speed up encryption performance. Performance could be further improved by enabling hardware-accelerated encryption, which the Nexus 6 still doesn't use, but Google has been experimenting with the feature in the Android Open Source Project.

Google also changed the way the Nexus 6 CPU works. In Android 5.0, when the device was idle with the screen on, two of the Nexus 6 CPU cores would shut down. 5.1 runs in quad-core mode all the time. Theoretically, this setup uses more battery power, but the majority of device power usage is consumed by the screen, not the CPU.

Device Protection

The new device protection screens that pop up during setup.

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Wipe the device and you'll see this during the next setup. This isn't the sign-in screen—it's a "prove you didn't steal this" screen.

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Device Protection is the biggest new feature of 5.1. Android has had security features like remote location, remote locking and erasing, and secure lockscreens for years, but if a thief only wants to steal your hardware, wiping the device would bypass all of those protections. Device Protection now allows you to nuke the device remotely but also keep the password in place, making the phone useless unless the new user knows the old account name and password. Device Protection also kicks in if the device is wiped through fastboot or other developer tools. The feature is roughly equivalent to the Activation Lock feature that Apple introduced for all iDevices in iOS 7.

Device Protection isn't enabled by the user; it automatically turns on when you set a secure lock screen (PIN, Pattern, or Password). It can also be remotely enabled by locking the phone through the Android Device Manager. After a protected phone is wiped, a new screen pops up during the setup process asking for the e-mail and password of an account previously used on the phone—no account, no access. Pass the verification and you proceed to device sign-in like normal. (Of course, all bets are off if your device is rooted or you have an unlocked bootloader.)

It's unclear what older devices will get Device Protection. All new devices that ship with 5.1 will have it, but devices that get the new OS as an upgrade might not get the new feature. In our limited testing, for instance, the Nexus 6 and 9 have Device Protection, but the Nexus 5 does not.

Other small changes

Drop-down arrows have been added to the Wi-Fi and Bluetooth quick settings. Tapping them opens new panels that allow you to connect to devices.

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Here are the new Wi-Fi and Bluetooth panels. "More settings" will jump to the respective sections in the system settings.

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Volume controls now show icons for each mode. The Notification LED now blinks in "None" mode, too.

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When tapped, the volume controls now have an "until next alarm" option—perfect for making the phone shut up while you take a nap.

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It's also now possible to control the notification volume while music is playing—just tap the bell icon.

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There's a new option in "downtime," Android's "do not disturb" mode. Before, it would only activate "priority mode," which let messages through from important contacts, but now you can pick "none" via the new option at the bottom.

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Heads-up notifications, which allow important apps to pop notifications up over the screen, got a new feature. It looks the same, but now a swipe up will dismiss the popup but keep the notification.

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Screen pinning is a "Kiosk Mode" that debuted in 5.0. It sticks a single app on the screen and doesn't allow the user to exit it unless they know the key combo. The popup is different.

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More importantly, you can now set screen pinning to lock the device after an app is unpinned, which makes it a lot more useful and secure. Before, anyone could exit it by following the on-screen instructions.

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New animations! The clock tab icons are all animated now.

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More animations! The screen orientation button now spins around when you press it.

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Contacts jumped from 1.0 to 1.1, and now the edit screen has an airier layout and icons.

The scrollbars in a few apps are different now. They get a chunky outline.

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Here we're interested in the status bar. Before, when you didn't have a SIM card installed, you just got an empty signal meter. Now you get a "no SIM card" icon.

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If you have a SIP calling option set up, you'll be prompted with a slightly updated interface when you make a call.

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The status screen now sticks SIM and IMEI information in their own sections. This page is a lot cleaner now.

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The time-picker layout has changed. The AM and PM circles at the bottom are gone. Now you tap on the AM and PM next to the time to change from one to the other.

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There is now new artwork for the default app icon (top) and Android Beam (bottom)

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This isn't quite 5.1 related, but Google introduced a new Play Store toolbar with the launch of 5.1. It's a search bar.

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5.1 also makes many small interface changes, documented in the gallery above. Notification and volume controls have seen improvement, and the OS has been tweaked and polished all over.

In addition, 5.1 brings built-in support for dual SIMs (previously something OEMs had to add) and HD Voice support.

Android 5.1 is one of the smaller minor version Android updates, down there with versions 4.2 and 4.3. But it brings a few nice changes and thankfully seems to solve many of the Nexus 6 performance problems.

Ron Amadeo
Ron is the Reviews Editor at Ars Technica, where he specializes in Android OS and Google products. He is always on the hunt for a new gadget and loves to rip things apart to see how they work. Emailron.amadeo@arstechnica.com//Twitter@RonAmadeo